Method of manufacturing sealing apparatus and mold

Abstract

A method of manufacturing a sealing apparatus. A rubber-like elastic material for forming a rubber-like elastic material sealing lip and a resin material for forming a resin sealing lip are placed within a mold for manufacturing a sealing apparatus by effecting vulcanization forming. The mold is clamped with contents placed therein, and the contents are pressurized and heated. During this process, a surface of the resin material is pressed by the forming pressure of the fluidized rubber-like elastic material against a thread formed on an inner wall surface the mold, thereby forming a thread groove on that surface of the resin material pressed against the thread.

What is claimed is: 
     
       1. A method of manufacturing a sealing apparatus comprising the steps of: preparing a mold for manufacturing the sealing apparatus by effecting vulcanization forming, said mold having threads formed on an inner wall surface thereof;   placing within said mold a rubber-like elastic material and a resin material for providing sealing lips of the sealing apparatus; and   clamping said mold in such a manner that said rubber-like material is pressurized and vulcanization formed thereby forming a portion of said rubber-like elastic material as a radially-inner sealing lip, so that the radially-inner sealing lip of the rubber-like elastic material overlaps and extends beyond the sealing lip of the resin material while a radially-inner surface of said resin material which is to serve as a surface of the sealing lip is pressed against said threads by forming pressure generated by fluidized rubber-like elastic material during the vulcanization forming, thereby forming a thread groove on that surface of said resin material; and   cutting off a superfluous portion of molded rubber-like elastic material which extends from the radially-inner sealing lip formed of said rubber-like elastic material.   
     
     
       2. A method of manufacturing a sealing apparatus according to claim 1, wherein, before the vulcanization forming, said resin material has a portion already formed as the sealing lip. 
     
     
       3. A method of manufacturing a sealing apparatus according to claim 1, wherein said resin material is washer-shaped, a radially inner end portion of said resin material being bent into a cylindrical shape by forming pressure generated during the vulcanization forming so as to be formed into the sealing lip. 
     
     
       4. A method of manufacturing a sealing apparatus according to any of claims 1, 2 or 3, wherein a back-up ring is placed within said mold together with said resin material and said rubber-like elastic material so that said back-up ring will be formed integrally with said materials. 
     
     
       5. A method of manufacturing a sealing apparatus according to claim 4, wherein said back-up ring has a bore formed therein, said bore allowing the entrance therein of a part of said resin material under forming pressure generated during the vulcanization forming, thereby allowing the integration of said back-up ring and said resin material.